Mothers age 40 or older have more sons and daughters left than young women. According to a study in Canada, the probability of being a left-handed child doubles for adult mothers.
The main reason is because adult mothers have more problems than young women during pregnancy and childbirth.
Led by Stanley Loren of Vancouver University, he conducted a survey of 2,228 university students. Some questions were asked about the age of the mother at birth and whether the student was left or right.
The data obtained were very representative. Mother 30If I was up to 35 years old, the child had a 25% chance of being left. Mother 35 If she was up to 39 years old, the probability was 40% and finally, if the mother was over 40 years old, the probability was 58%.
These investigations should only be considered as curiosities, but it seems that in these cases a certain "neurological disorder" occurs.
If you are on the left, reader, you can prove what is said here.